New design seismic streamers presently used in seismic marine exploration have a surrounding plug of urethane foam around each of the hydrophones. This foam is effective in dampening noise in the signal. To further isolate the hydrophones from noise, the entire streamer body including the foam plugs, is filled with a highly refined oil, e.g., a kerosene-like cut. Due to imperfect displacement by the oil many air bubbles are retained by the foam plugs after filling with oil. These retained air bubbles are time consuming to remove. Presence of these air bubbles in the oil/foam surrounding the hydrophone sensors causes serious signal degradation. Because the streamer body is made of polyvinyl-chloride (PVC) and not designed to withstand differential pressure, the air cannot be evacuated nor can pressurized oil be used to fill the streamer.
Therefore, what is needed is a method to effectively remove air bubbles entrained in oil/foam surrounding the hydrophone sensors so as to avoid serious signal degradation.